Conductive adhesive

a conductive adhesive and paste-like technology, applied in the direction of non-macromolecular adhesive additives, conductors, metal/alloy conductors, etc., can solve the problems of lowering the long-term reliability of in-vehicle electronic devices and modules, lowering the connection strength, and lowering the adhesive strength between the metal surface and the cured conductive product. , to achieve the effect of lowering the adhesive strength, excelling in the adhesive strength to the metal surfa

Active Publication Date: 2009-04-28
DENSO CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the melting temperature of the lead-free solder using tin as the mother material is still higher than the melting temperature of conventional Sn—Pb eutectic solder by 20° C. or more, and thus in the solder joining / reflow processing temperature in the mounting step, there remains still somewhat fear that it would cause unnecessary damage by heat to electronic parts.
Similarly, when the electrical joints of the electric parts to the substrate circuit is exposed to high-temperature, high-humidity conditions, the elevation of contact resistance or lowering of connection strength due to the formation of metal oxides in the joining interface by the effect of humidity (moisture) invading from such an environment is also the factor for lowering the long-term reliability of in-vehicle electronic devices and modules.

Method used

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Examples

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examples

[0062]The present invention will be more specifically illustrated hereunder referring to examples. Although these examples are certain examples of the best modes for carrying out the present invention, the scope of the present invention is in no way limited to these specific examples.

[0063]For evaluating the properties and performances of paste-like conductive adhesives (conductive paste) disclosed in the following examples and comparative examples, each evaluation item was measured using the below-described procedures and conditions.

I. Resin Properties of Epoxy Thermosetting Resin per se used in Paste-like Conductive Adhesives

[0064][Glass Transition Temperature (Tg)]

[0065]A cured resin product of the epoxy thermosetting resin per se is prepared under curing conditions of 150° C. and 60 minutes. For the obtained cured resin product, the glass transition temperature (Tg) is measured using a DSC (differential scanning calorimeter) under a condition that temperature elevation rate is s...

examples 1 to 5

[0099]Spherical silver powder having an average particle diameter of 3 μm was employed as the metal powder for the conductive medium to be blended in the conductive paste; and the spherical silver powder was evenly dispersed by stirring in the one-component epoxy thermosetting resin component to prepare the conductive paste of the compounding composition listed in Table 1.

[0100]In said one-component epoxy thermosetting resin component,

[0101]used for the epoxy resin component thereof were

[0102]Epiclon HP-4032D (product of JER; 1,6-dihydroxynaphthalene diglycidyl ether, epoxy equivalent: 142) as the epoxy compound having naphthalene skeletons;

[0103]THATGE (1,2,10-trihydroxyanthracene triglycidyl ether, epoxy equivalent: 142) as the trifunctional epoxy compound having anthracene skeletons,

[0104]Epikote 828EL, which is a bisphenol A-type epoxy resin (product of JER; epoxy equivalent: 187), or Epiclon HP-7200, which is a dicyclopentadiene-type epoxy resin (product of JER; epoxy equivalen...

example 6

[0117]In comparison with the aforementioned conductive paste of Example 1, C11-Z-CN (product of Shikoku Chemicals Corporation; 1-cyanoethyl-2-undecyl imidazole; melting point: about 50° C.; molecular weight: 275) was employed as a cure accelerator in place of 2E4MZ-CN, and, with this exception, otherwise the same compounding conditions were chosen to prepare a conductive paste having the composition listed in Table 2.

[0118]In similar way as in Examples 1 to 5, in Example 6, in the one-component epoxy thermosetting resin component therefor, the content ratio of the epoxy compound having naphthalene skeletons to other epoxy compounds was 3:1, and on the other hand, the blending ratio of 0.9 molecule of the above-described dicarboxylic-acid derived cyclic acid anhydride to 2 epoxy groups was selected. In addition, 0.016 mole of the imidazole compound, which is a cure accelerator, was added to 1 mole of the epoxy group. Further, a silane coupling agent was added at a ratio of 1.0 part b...

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Abstract

The present invention provides a conductive adhesive that is applicable as means for forming conductive junction to process for surface mounting of electronic parts for vehicle loading and process for the manufacture of the electronic parts per se for the purpose of substituting soldering therewith. The conductive adhesive according to the present invention is a conductive adhesive produced by dispersing a conductive medium, such as silver powder, in a binder resin component of a one-component epoxy thermosetting resin which has such a composition that the resin comprises, as essential components, an epoxy resin component composed mainly of an epoxy compound with a polycyclic aromatic ring skeleton, and a cyclic acid anhydride as a curing agent component thereof, and is further added with a coupling agent as an adherence imparting agent therefor.

Description

[0001]This application is the U.S. National Phase under 35 U.S.C. §371 of International Application PCT / JP2005 / 001941, filed Feb. 9, 2005, which claims priority to Japanese Patent Application No. 2004-036213, filed Feb. 13, 2004. The International Application was not published under PCT Article 21(2) in English.[0002]1. Technical Field[0003]The present invention relates a paste-like conductive adhesive using metal powder as a conductive medium, and profitably employing epoxy thermosetting resin as a binder thereof; more specifically to a conductive adhesive that is applicable to provide conductive junction in mounting of electronic parts in place of soldering.[0004]2. Background Art[0005]In the process for assembling electronic devices or mounting electronic parts, as means for achieving conductive junction between circuit wiring and individual electronic parts, soldering is widely used. In recent years, use of lead-free solder containing no lead as a material for soldering has been...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C08K5/04C09J163/00C08L63/00C09J9/02C09J11/04C09J11/06H01B1/00H01B1/22H05K3/32
CPCC08G59/42C09J9/02C09J163/00H01B1/22H05K3/321C08L63/00H05K2201/0239
Inventor TERADA, NOBUTOSHIOI, NAOTOTOTOKAWA, MASASHININOMIYA, YASUNORI
Owner DENSO CORP
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